Why You're Probably Related to Nefertiti, Confucius, and Socrates
How far back in time would you need to travel to find a common human ancestor of people living today? The answer is surprisingly recent.
The theory of evolution holds that all living things have common ancestors. But just how far back do humans need to go to find a common ancestor of their own: a person to whom all living people are related?
The answer, for people of European descent at least, is surprisingly recent: 600 years. The common ancestor for every single person alive on the planet today, no matter where, lived approximately 3,600 years ago. That means Confucius, Nefertiti, Socrates, and any figure from ancient history that had children, is in some way your ancestor.
This comes to light through a new book by Adam Rutherford titled A Brief History of Everyone Who Ever Lived, which explores efforts within mathematics and science to describe human ancestry on a grand scale.
“We are all special, which also means that none of us is,” writes Rutherford in the book. “This is merely a numbers game. You have two parents, four grandparents, eight great-grandparents, and so on. Each generation back the number of ancestors you have doubles. But this ancestral expansion is not borne back ceaselessly into the past. If it were, your family tree when Charlemagne was Le Grand Fromage would harbor around 137,438,953,472 individuals on it—more people than were alive then, now, or in total.”
So how do we make sense of this numerical discrepancy? It helps to view our family lineage as an entangled web instead of a neat “family tree.”
“You can be, and in fact are, descended from the same individual many times over,” Rutherford writes. “Your great-great-great-great-great-grandmother might hold that position in your family tree twice, or many times, as her lines of descent branch out from her, but collapse onto you. The further back through time we go, the more these lines will coalesce on fewer individuals.”
The startling discovery that all Europeans might share a common ancestor who walked the Earth just 600 years ago was first proposed in 1999 by a Yale statistician named Joseph Chang. In his paper “Recent Common Ancestors of All Present-Day Individuals,” Chang used complex mathematical concepts—like Poisson distributions and Markov chains—to show how webbed pedigrees can overlap to produce common ancestors.
So if all living Europeans have a common ancestor who lived around the year 1400, what happens when you look further back into the past?
Chang's calculations suggest that about one fifth of Europeans who lived a millennium ago have no living ancestors today. This seems to be because their ancestral line died off along the way. Conversely, as Rutherford writes, the implication is that everyone else alive a millennium ago is related to Europeans alive today.
“One way to think of it is to accept that everyone of European descent should have billions of ancestors at a time in the tenth century, but there weren’t billions of people around then, so try to cram them into the number of people that actually were. The math that falls out of that apparent impasse is that all of the billions of lines of ancestry have coalesced into not just a small number of people, but effectively literally everyone who was alive at that time.”
Chang's complex mathematical paper concludes with a passage that's rather poetic for a numbers guy:
"Our findings suggest a remarkable proposition: no matter the languages we speak or the color of our skin, we share ancestors who planted rice on the banks of the Yangtze, who first domesticated horses on the steppes of the Ukraine, who hunted giant sloths in the forests of North and South America, and who labored to build the Great Pyramid of Khufu."
Still, mapping out an exact pedigree for an individual is exceedingly difficult. For instance, the “family trees” that Ancestry.com provides its users only go back up to 10 generations—sometimes less if users want more reliable results. Often someone's luck with tracing their family lineage comes down to whether or not they can find documents that detail the lives of their ancestors. At a certain point, the act of tracing family lineage becomes purely theoretical, as Mark Humphrys, a computer scientist at Dublin City University, told Steve Olson in an article for The Atlantic:
“You can ask whether everyone in the Western world is descended from Charlemagne, and the answer is yes, we're all descended from Charlemagne. But can you prove it? That's the game of genealogy.”
Swipe right to make the connections that could change your career.
Swipe right. Match. Meet over coffee or set up a call.
No, we aren't talking about Tinder. Introducing Shapr, a free app that helps people with synergistic professional goals and skill sets easily meet and collaborate.
A growing body of research shows promising signs that the keto diet might be able to improve mental health.
- The keto diet is known to be an effective tool for weight loss, however its effects on mental health remain largely unclear.
- Recent studies suggests that the keto diet might be an effective tool for treating depression, and clearing up so-called "brain fog," though scientists caution more research is necessary before it can be recommended as a treatment.
- Any experiments with the keto diet are best done in conjunction with a doctor, considering some people face problems when transitioning to the low-carb diet.
She met mere mortals with and without the Vatican's approval.
- For centuries, the Virgin Mary has appeared to the faithful, requesting devotion and promising comfort.
- These maps show the geography of Marian apparitions – the handful approved by the Vatican, and many others.
- Historically, Europe is where most apparitions have been reported, but the U.S. is pretty fertile ground too.
Thinking your life is worthwhile is correlated with a variety of positive outcomes.
- A new study finds that adults who feel their lives are meaningful have better health and life outcomes.
- Adults who felt their lives were worthwhile tended to be more social and had healthier habits.
- The findings could be used to help improve the health of older adults.
SMARTER FASTER trademarks owned by The Big Think, Inc. All rights reserved.